Book Review

The Science of Desire: The search for the gay gene and the biology of behavior

N Engl J Med 1995; 332:1311-1312May 11, 1995

Article

The Science of Desire: The search for the gay gene and the biology of behavior
By Dean Hamer and Peter Copeland. Approximately 217 pp. New York, Simon & Schuster, 1994. $23. ISBN: 0-671-88724-6

Hamer and Copeland tell a good story. Their book describes how Hamer and his colleagues searched for and found evidence of genetic linkage in male homosexuality. Their finding of a correlation between homosexual orientation and the inheritance of polymorphic markers on the X chromosome in 64 percent of 40 pairs of homosexual brothers has created a stir in the scientific community. It has inflamed the nature-versus-nurture debate, caused both excitement and concern in the gay community, and led to intense speculation about what can really be inherited in an area as complicated as human sexuality.

The book is a well-written tale of how science is created. Hamer, who is chief of the Section on Gene Structure and Regulation at the National Cancer Institute, spent most of his career studying the regulation of metallothionein gene transcription by heavy-metal ions, largely in yeast cells and mice. He cites a mixture of curiosity, altruism, and boredom as the reasons for switching to such a highly controversial topic as sexual orientation. At that time the state of genetic research in this area was sufficient to convince him that the scientific study of sex could benefit from advances in genetic mapping and might make the debates about sexual orientation more scientific and less political. Having gathered an impressive crew of investigators he began to examine pedigrees and confirmed the likelihood of an X-linked trait with the finding of an excess of homosexual maternal uncles and male cousins in families of male homosexuals. Furthermore, the search for likely regions on the X chromosome led to an extensive analysis of the Xq28 region of the sex chromosome and to the finding referred to above. Since the publication of their findings in July 1993 Hamer and his colleagues have been very busy addressing the obvious questions about the implications of this research, as well as the harsher criticisms.

Clearly, this research needs to be replicated, and if the results are reproduced, more work needs to be done to find the gene responsible for whatever is being inherited. Hamer is cautious in extrapolating his findings to larger issues. He states clearly that his study is evidence of a genetic factor influencing the development of homosexuality in a particular sample of homosexual men with homosexual brothers. He does not dismiss the probable role of environmental factors, either in this sample or in other forms of homosexuality. He also argues reasonably for the importance of research in this area and argues that such endeavors must be allowed to be separate from the political and ethical debate surrounding homosexuality.

Despite Hamer's cautions, his use of the term “gay gene” is somewhat misleading. We can relate to the need to find simple terminology to help the public understand this highly complex field, but the term implies more than Hamer's work establishes. In this respect, the public and even the professional community have understandably overreacted to these findings as though they were proof of the biologic basis and with it the immutability of homosexuality. In a similar vein, the least well thought out and presented part of this book is the section on psychological theories. Given that Hamer is not trained in psychology or psychiatry, it is understandable that this area is less well covered. However, even its subtitle, “Sissies, Freud, and Sex Acts,” suggests a hasty dismissal of the importance of psychological theories.

Overall, this book makes enjoyable reading, particularly for anyone interested in the making of science as it relates to human behavior or sexuality.

Susan J. Bradley, M.D.
University of Toronto, Toronto, ON M5G IX8, Canada